The King's favourite drink has been revealed and he takes his own glass to enjoy it on his travels.
Charles III is partial to a strong cocktail before dinner every night, according to royal commentator Gordon Rayner.
His daily tipple is made with half gin and half dry vermouth, garnished with an olive or lemon twist.
Reports suggest His Majesty takes the ingredients with him when travelling overseas.
The 74-year-old even takes along his own glass meaning the drink is always made just the way he likes it.
It is said he enjoys the drink stirred, not shaken, according to previous reports.
Queen Camilla also takes her own supply of red wine on holiday, which typically comes from Bordeaux.
But it is not as complex as the King's martinis which supposedly have to be served in a particular way.
"When he travels abroad he takes his own spirits with him to be mixed by his staff to his precise taste," Mr Rayner told The Telegraph.
"While the Queen takes her own supply of red wine, usually from the Pomerol appellation of Bordeaux.
The King remains health conscious and has an almost perfect body mass index of 22.8, according to Mr Rayner.
While he may sip a glass of wine during dinner, his martini "is effectively his only drink of the day," Mr Rayner added.
Charles' diet has made numerous headlines over the years, like starting each day with nuts and seeds.
He has also addressed the myth that he has seven boiled eggs served to him, to only eat the one that looks most fitting.
While this claim proved to be false, chef Graham Tinsley once revealed that the King does eat a boiled egg with every single meal.
He also enjoy fresh fruit as well as drinking loose leaf green tea with organic honey, and requires his water to be heated specifically to 70C.
A lover of the outdoors, His Majesty is known to take hour-long walks across the hills and moors of Balmoral while staying at the royal estate in Scotland.
Despite being faced with exquisite banquets and dishes during his royal duties, he is said to keep up a flexitarian diet steering away from fish and meat at least twice a week.
He is also said to avoid dairy once per week.
